Molecular testing is a test carried out at the molecular level for detection of biological materials, such as DNA, RNA and/or proteins, in a test sample. Molecular testing is beginning to emerge as a gold standard due to its speed, sensitivity and specificity. For example, molecular assays were found to be 75% more sensitive than conventional cultures when identifying enteroviruses in cerebrospinal fluid and are now considered the gold standard for this diagnostic (Leland et al., Clin. Microbiol Rev. 2007, 20:49-78).
Molecular assays for clinical use are typically limited to identification of less than six genetic sequences in a single reaction (i.e, real-time PCR assays). Microarrays, which are patterns of molecular probes attached to a solid support, are one way to increase the number of sequences that can be uniquely identified. However, the workflow is typically complex and requires molecular amplification prior to incubation, or hybridization, with the microarray. Separate amplification and hybridization allows the vessels for amplification to be designed for efficient thermal transfer; however, the fluidic complexity is considerable. Combining amplification and hybridization is one way to simplify the fluidics and operational complexity; however, this approach can suffer from thermal transfer inefficiencies because the reaction vessel often consists of a thermally inefficient boundary or support to which the microarrays can be attached.